hashset implemented (with tests)

sets/hashset/hashset.go

@@ -0,0 +1,101 @@
+/*
+Copyright (c) Emir Pasic, All rights reserved.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 3.0 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library. See the file LICENSE included
+with this distribution for more information.
+*/
+
+// Implementation of set backed by a hash table.
+// Structure is not thread safe.
+// References: http://en.wikipedia.org/wiki/Set_%28abstract_data_type%29
+
+package hashset
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Set struct {
+	items map[interface{}]struct{}
+}
+
+var itemExists = struct{}{}
+
+// Instantiates a new empty set
+func New() *Set {
+	return &Set{items: make(map[interface{}]struct{})}
+}
+
+// Adds the items (one or more) to the set.
+func (set *Set) Add(items ...interface{}) {
+	for _, item := range items {
+		set.items[item] = itemExists
+	}
+}
+
+// Removes the items (one or more) from the set.
+func (set *Set) Remove(items ...interface{}) {
+	for _, item := range items {
+		delete(set.items, item)
+	}
+}
+
+// Check wether items (one or more) are present in the set.
+// All items have to be present in the set for the method to return true.
+// Returns true if no arguments are passed at all, i.e. set is always superset of empty set.
+func (set *Set) Contains(items ...interface{}) bool {
+	for _, item := range items {
+		if _, contains := set.items[item]; !contains {
+			return false
+		}
+	}
+	return true
+}
+
+// Returns true if set does not contain any elements.
+func (set *Set) Empty() bool {
+	return set.Size() == 0
+}
+
+// Returns number of elements within the set.
+func (set *Set) Size() int {
+	return len(set.items)
+}
+
+// Clears all values in the set.
+func (set *Set) Clear() {
+	set.items = make(map[interface{}]struct{})
+}
+
+// Returns all items in the set.
+func (set *Set) Values() []interface{} {
+	values := make([]interface{}, set.Size())
+	count := 0
+	for item, _ := range set.items {
+		values[count] = item
+		count += 1
+	}
+	return values
+}
+
+func (set *Set) String() string {
+	str := "HashSet\n"
+	items := []string{}
+	for k, _ := range set.items {
+		items = append(items, fmt.Sprintf("%v", k))
+	}
+	str += strings.Join(items, ", ")
+	return str
+}

sets/hashset/hashset_test.go

@@ -0,0 +1,83 @@
+/*
+Copyright (c) Emir Pasic, All rights reserved.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 3.0 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library. See the file LICENSE included
+with this distribution for more information.
+*/
+
+package hashset
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestHashSet(t *testing.T) {
+
+	set := New()
+
+	// insertions
+	set.Add()
+	set.Add(1)
+	set.Add(2)
+	set.Add(2, 3)
+	set.Add()
+
+	if actualValue := set.Empty(); actualValue != false {
+		t.Errorf("Got %v expected %v", actualValue, false)
+	}
+
+	if actualValue := set.Size(); actualValue != 3 {
+		t.Errorf("Got %v expected %v", actualValue, 3)
+	}
+
+	// Asking if a set is superset of nothing, thus it's true
+	if actualValue := set.Contains(); actualValue != true {
+		t.Errorf("Got %v expected %v", actualValue, true)
+	}
+
+	if actualValue := set.Contains(1); actualValue != true {
+		t.Errorf("Got %v expected %v", actualValue, true)
+	}
+
+	if actualValue := set.Contains(1, 2, 3); actualValue != true {
+		t.Errorf("Got %v expected %v", actualValue, true)
+	}
+
+	if actualValue := set.Contains(1, 2, 3, 4); actualValue != false {
+		t.Errorf("Got %v expected %v", actualValue, false)
+	}
+
+	set.Remove()
+	set.Remove(1)
+
+	if actualValue, expactedValues := fmt.Sprintf("%d%d", set.Values()...), [2]string{"23", "32"}; actualValue != expactedValues[0] && actualValue != expactedValues[1] {
+		t.Errorf("Got %v expected %v", actualValue, expactedValues)
+	}
+
+	if actualValue := set.Contains(1); actualValue != false {
+		t.Errorf("Got %v expected %v", actualValue, false)
+	}
+
+	set.Remove(1, 2, 3)
+
+	if actualValue := set.Contains(3); actualValue != false {
+		t.Errorf("Got %v expected %v", actualValue, false)
+	}
+
+	if actualValue := set.Empty(); actualValue != true {
+		t.Errorf("Got %v expected %v", actualValue, true)
+	}
+
+}

stacks/linkedliststack/linkedliststack.go

@@ -80,7 +80,7 @@ func (stack *Stack) Size() int {
 }
 
 func (stack *Stack) String() string {
-	str := "RedBlackTree\n"
+	str := "LinkedListStack\n"
 	element := stack.top
 	elementsValues := []string{}
 	for element != nil {